diff --git a/readium/navigators/web/fixedlayout/src/main/kotlin/org/readium/navigator/web/fixedlayout/spread/SpreadWebView.kt b/readium/navigators/web/fixedlayout/src/main/kotlin/org/readium/navigator/web/fixedlayout/spread/SpreadWebView.kt
index a8f86f2841..06db12a04a 100644
--- a/readium/navigators/web/fixedlayout/src/main/kotlin/org/readium/navigator/web/fixedlayout/spread/SpreadWebView.kt
+++ b/readium/navigators/web/fixedlayout/src/main/kotlin/org/readium/navigator/web/fixedlayout/spread/SpreadWebView.kt
@@ -37,6 +37,7 @@ import org.readium.navigator.web.internals.webview.RelaxedWebView
 import org.readium.navigator.web.internals.webview.WebView
 import org.readium.navigator.web.internals.webview.WebViewScrollController
 import org.readium.navigator.web.internals.webview.WebViewState
+import org.readium.navigator.web.internals.webview.invokeOnWebViewUpToDate
 import org.readium.r2.shared.ExperimentalReadiumApi
 import org.readium.r2.shared.util.AbsoluteUrl
 
@@ -96,8 +97,7 @@ internal fun SpreadWebView(
             documentStateApi?.let { documentStateApi ->
                 documentStateApi.listener = DelegatingDocumentApiListener(
                     onDocumentLoadedAndSizedDelegate = {
-                        webView.requestLayout()
-                        webView.setNextLayoutListener {
+                        webView.invokeOnWebViewUpToDate {
                             val scrollController = WebViewScrollController(webView)
                             scrollController.moveToProgression(
                                 progression = progression,
diff --git a/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/pager/RenditionScrollState.kt b/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/pager/RenditionScrollState.kt
index d53e8d54e7..f5b89c5c35 100644
--- a/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/pager/RenditionScrollState.kt
+++ b/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/pager/RenditionScrollState.kt
@@ -183,7 +183,7 @@ public class RenditionScrollState(
             return
         }
 
-        val scrollController = pageStates[index].scrollController.value!!
+        val scrollController = pageStates[index].scrollController.value ?: return
         val scrolled = scrollController.scrollToMax(orientation)
         if (scrolled > 0) {
             dispatchRawDelta(scrolled.toFloat())
diff --git a/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/webview/RelaxedWebView.kt b/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/webview/RelaxedWebView.kt
index b561c4144a..4d9789e611 100644
--- a/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/webview/RelaxedWebView.kt
+++ b/readium/navigators/web/internals/src/main/kotlin/org/readium/navigator/web/internals/webview/RelaxedWebView.kt
@@ -66,8 +66,9 @@ public class RelaxedWebView(context: Context) : WebView(context) {
     @Deprecated("Deprecated in Java")
     override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
         super.onLayout(changed, l, t, r, b)
-        nextLayoutListener.invoke()
+        val listener = nextLayoutListener
         nextLayoutListener = {}
+        listener.invoke()
     }
 
     private var hasActionMode: Boolean = false
@@ -140,8 +141,12 @@ private class CallbackDecorator(
  * has received data up-to-date at the moment when the call occurs or newer.
  */
 public fun RelaxedWebView.invokeOnWebViewUpToDate(block: WebView.() -> Unit) {
-    requestLayout()
-    setNextLayoutListener {
+    if (verticalScrollExtent > 0 && horizontalScrollExtent > 0) {
         invokeOnReadyToBeDrawn(block)
+    } else {
+        requestLayout()
+        setNextLayoutListener {
+            invokeOnWebViewUpToDate(block)
+        }
     }
 }
diff --git a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipContainer.kt b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipContainer.kt
index 18ad265bf9..0828b9831a 100644
--- a/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipContainer.kt
+++ b/readium/shared/src/main/java/org/readium/r2/shared/util/zip/FileZipContainer.kt
@@ -17,6 +17,8 @@ import kotlinx.coroutines.DelicateCoroutinesApi
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withContext
 import org.readium.r2.shared.InternalReadiumApi
 import org.readium.r2.shared.extensions.readFully
@@ -42,6 +44,8 @@ internal class FileZipContainer(
     file: File,
 ) : Container<Resource> {
 
+    private val mutex = Mutex()
+
     private inner class Entry(private val url: Url, private val entry: ZipEntry) :
         Resource {
 
@@ -76,20 +80,30 @@ internal class FileZipContainer(
             }
 
         override suspend fun read(range: LongRange?): Try<ByteArray, ReadError> =
-            try {
-                withContext(Dispatchers.IO) {
-                    val bytes =
-                        if (range == null) {
-                            readFully()
-                        } else {
-                            readRange(range)
-                        }
-                    Try.success(bytes)
+            mutex.withLock {
+                try {
+                    withContext(Dispatchers.IO) {
+                        val bytes =
+                            if (range == null) {
+                                readFully()
+                            } else {
+                                readRange(range)
+                            }
+                        Try.success(bytes)
+                    }
+                } catch (e: ZipException) {
+                    Try.failure(ReadError.Decoding(e))
+                } catch (e: IOException) {
+                    Try.failure(ReadError.Access(FileSystemError.IO(e)))
+                } catch (e: IllegalStateException) {
+                    Try.failure(
+                        ReadError.Access(
+                            FileSystemError.IO(
+                                IOException("Zip file closed.", e)
+                            )
+                        )
+                    )
                 }
-            } catch (e: ZipException) {
-                Try.failure(ReadError.Decoding(e))
-            } catch (e: IOException) {
-                Try.failure(ReadError.Access(FileSystemError.IO(e)))
             }
 
         private suspend fun readFully(): ByteArray =
@@ -156,9 +170,11 @@ internal class FileZipContainer(
     @OptIn(DelicateCoroutinesApi::class)
     override fun close() {
         GlobalScope.launch {
-            tryOrLog {
-                withContext(Dispatchers.IO) {
-                    archive.close()
+            mutex.withLock {
+                tryOrLog {
+                    withContext(Dispatchers.IO) {
+                        archive.close()
+                    }
                 }
             }
         }